Fetal abdomen scanning is routinely performed in obstetric practice. For example, fetal anatomic measurements pertaining to the femur length, cranial circumference and abdominal circumference are routinely performed during obstetric ultrasound scanning, and can be used as indicators of gestational age and fetal growth pattern.
In performing these measurements it is important that the fetal anatomy is imaged in the correct scan plane and that measurements are made consistent with clinical guidelines to ensure reproducibility of the measurements. There can be considerable variability in the maternal abdominal lining, fetal size and presentation with gestational age and movement that translates into variability in the texture, scale, intensity, and noise, in addition to the presence of artifacts in ultrasound images. Therefore, while obtaining the correct scan plane and making a manual measurement with a mouse-like caliper provided in an ultrasound scanner can be a matter of routine for an expert sonographer, making such a measurement may be confounding for a novice user or mid-wife. This is particularly true of soft tissue imaging, since the impedance mismatch at a soft tissue boundary is much less pronounced than at boundaries of bony structures, and therefore soft-tissue appearance can be obfuscated by proximal anatomies and speckle noise. Soft tissue is also prone to artifacts arising from its inherent deformability. Conventional techniques for mitigating some of these issues can inadequately address the problem of guiding the clinician towards a correct scan plane for making reproducible measurements.